The present invention relates to a self-propelled apparatus for removing a thickness of asphalt paving from an asphalt roadway, and more particularly to a novel cutting drum utilized in such apparatus.
Deteriorating asphalt roadways have in the past been rehabilitated by a process wherein the top layer of the asphalt roadway is removed by a drum type milling machine which is advanced along the roadway. The removed asphalt is then trucked to a reprocessing plant where it is usually blended with new aggregate and hot liquid asphalt in a rotary heater to form a new asphalt paving material. This new material is then trucked back to the roadway while hot and laid on the roadway by a conventional paver. Milling machines of the described type are disclosed for example, in U.S. Pat. No. 4,697,850 to Tuneblom, U.S. Pat. No. 4,480,873 to Latham, and U.S. Pat. No. 4,193,636 to Jakob.
As an alternative to the above process, U.S. Pat. No. 4,946,307 to Jakob discloses an apparatus for the cold, in-place recycling of asphalt, and which includes a cylindrical milling drum mounted at a medial location along its longitudinal length for removing a thickness of the asphalt paving.
The cutting teeth of the drums of the prior art milling machines commonly include a tooth holder which mounts a removable tooth. The teeth rapidly wear out during operation, and must be replaced on an almost daily basis, and in addition, the holders commonly break and must also be replaced. The replacement of the teeth and holders thus presents a significant maintenance problem, which is complicated by the fact that the teeth and holders often become coated with asphalt which tends to "weld" the components in place and renders them difficult to remove.
It is accordingly an object of the present invention to provide an apparatus for milling a roadway surface and which has a cutter drum with cutting assemblies which are constructed to avoid excessive wear and so as to reduce the likelihood of damage to the cutting teeth and holders.
It is a more particular object of the present invention to provide a cutter drum of the described type and which provides for the ready removal of both the cutting teeth and the tooth holders in the event they become damaged or worn.